Do you recognize this image ?

Concentrate on the four small dots in the middle of the picture for 30 – 40 secs. Then look at any smooth single coloured surface near you (wall, paper,…). You will see a circle of light developing. Now blink your eyes a couple of times and you will see an image emerging. Do you recognize the image ?

Blivet

A blivet, also known as a poiuyt, is an undecipherable figure, an optical illusion and an impossible object. It appears to have three cylindrical prongs at one end which then mysteriously transform into two rectangular prongs at the other end.

The Cosmonaut of the Erotic Future

The Cosmonaut of the Erotic Future by Aaron Schuster, A brief history of levitation from St. Joseph to Yuri Gagarin (Cabinet Magazine).

Related:

The levitation of Daniel Dunglas Home at Ward Cheney’s house interpreted in a lithograph from Louis Figuier, Les Mystères de la science 1887

Satire on False Perspective

Satire on False Perspective is the title of an engraving produced by William Hogarth in 1754.

The intent of the work is clearly given by the subtitle:

Whoever makes a DESIGN without the Knowledge of PERSPECTIVE will be liable to such Absurdities as are shewn in this Frontispiece

Message of Love from the Dolphins

Children will probably see a group of playing dolphins. But adults see usually something else. It’s called Message of Love from the Dolphins by Sandro Del-Prete (interesting site !).

The Porcupine Illusion

It began as an urbane fable about how to brush down bristling nerves. Sometime in the summer of 1909, not long before Sigmund Freud was due to embark on his only visit to the United States, he was enjoying a cigar in the company of his inner circle in the busy Biedermeier interior of Berggasse 19, when he suddenly announced, “I am going to America to catch sight of a wild porcupine and to give some lectures.”

A tale about Arthur Schopenhauer and Sigmund Freud and of course porcupines. See also hedgehog’s dilemma.

A Hidden Airplane Factory

During World War II the Army Corps of Engineers needed to hide the Lockheed Burbank Aircraft Plant to protect it from a Japanese air attack. They covered it with camouflage netting and fake buildings to make it look like a rural subdivision from the air. See the pictures

Ponzo’s Illusion

The Ponzo illusion is an optical illusion that was first demonstrated by the Italian psychologist Mario Ponzo (1882-1960) in 1913. He suggested that the human mind judges an object’s size based on its background. The upper horizontal line segment in the figure appears to be longer than the lower line segment despite the fact that both are the same length.

Hering illusion

The Hering illusion is an optical illusion due to the physiologist Ewald Hering (1861). The two horizontal lines are both straight, but they look as if they were bowed outwards. The distortion is produced by the lined pattern on the background, that simulates a perspective design, and creates a false impression of depth.

The Orbison illusion is one of its variants,

while the Wundt illusion produces a similar, but inverted effect.

The Orbison illusion is an optical illusion that was first described by the psychologist William Orbison in 1939. The bounding rectangle and inner square both appear distorted in the presence of the radiating lines. The background gives us the impression there is some sort of perspective. As a result, our brain sees the shape distorted.

The Wundt illusion is an optical illusion that was first described by the German psychologist Wilhelm Wundt in the 19th century. The two red horizontal lines are both straight, but they look as if they are bowed inwards. The distortion is induced by the crooked lines on the background, as in Orbison’s illusion. (In some illustrations the Wundt illusion uses two vertical lines, but the inverted effect compared to the Hering illusion is more obvious with horizontal lines)

More of this in The Nature of Visual Illusion by Mark Fineman.

Penrose triangle

The Penrose triangle, also known as the tribar, is an impossible object. It was first created by the Swedish artist Oscar Reutersvärd in 1934. The mathematician Roger Penrose independently devised and popularised it in the 1950s, describing it as “impossibility in its purest form”. It is featured prominently in the works of artist M.C. Escher, whose earlier depictions of impossible objects partly inspired it.